Storage or warehouse systems may include multi-level storage racks for storing loads, such as boxes, containers or pallets, at each of the multiple levels. Access to the stored loads may be provided by a shuttle system including multiple remotely controlled robotic devices or shuttles arranged on each level. The shuttles move back and forth in a single horizontal direction within one storage level to access stored goods arranged on the corresponding level and carry them.
A lifting mechanism, such as a forklift, is provided to move loads in a vertical direction from the ground to the respective level of the storage rack or from the respective level to the ground. The forklift lifts newly arriving goods to the respective level and loads them to the shuttles that deliver the goods to required storage cells at that level. Similarly, shuttles retrieve goods from the storage cells and deliver them to the forklift raised to the respective level. The forklift unloads the goods from the shuttles and moves them in a vertical direction down to the ground.
However, the number of lifts in any efficient storage system employing multiple shuttles is substantially less than the number of shuttles. Therefore, “bottlenecks” are created near the lifts, reducing the throughput of the storage system.
Therefore, there is a need for a new “self-lifting” technique that would enable a robotic device, such as a shuttle, to move in a vertical direction without assistance of an external lift.
Moreover, it would be desirable to provide a self-lifting robotic device capable of carrying loads, while it moves in a vertical direction. Such self-lifting devices would substantially increase the throughput of the storage system because the loads can be carried from one end point of the storage system to another, without inteimmediate points where robotic devices are loaded and unloaded.
Also, to increase the throughput of the storage system, it would be desirable to provide a self-lifting robotic device with a single structural element allowing the robotic device to perform vertical movement and loading at the same time, so as to place loads onto the robotic device and carry them while the robotic device moves in a vertical direction.